BUCHAREST, July 21 (Xinhua) -- Military aircraft fly over the Statue of Air Heroes during the Romanian Aviation and Air Force Day celebrations in Bucharest, Romania, July 20, 2020.

.DAMASCUS, July 21 (Xinhua) -- Syrian air defense missile is seen in the sky over Damascus, capital of Syria, on July 20, 2020. The Syrian air defenses responded to an Israeli missile attack over the capital Damascus on Monday evening, state news agency SANA reported.

WASHINGTON, D.C., July 21 (Xinhua) -- Visitors wearing face masks view exhibits in the West Building of the National Gallery of Art in Washington, D.C., the United States, July 20, 2020. Parts of the gallery reopened to the public on Monday after months of closure due to the COVID-19 pandemic.

PARIS, July 21 (Xinhua) -- A staff member (L) takes a mans blood sample for COVID-19 antibody rapid serological test at a pharmacy in Paris, France, July 20, 2020. To speed up the screening of COVID-19, French pharmacists have been authorized, since July 11 and until October 30, to carry out antibody rapid serological test which allows a simple drop of blood taken from the fingertip to be tested for the possible presence of antibodies against COVID-19 in about ten minutes.